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HomeMy WebLinkAbout251219 243 Great Pond Road - Stormwater Report - - 243 GREAT POND ROAD STORMWATER ANALYSIS AND CACLUATIONS FOR 243 GREAT POND ROAD IN NORTH ANDOVER, MASSACHUSETTS PREPARED BY: PATRIOT Engineering PO BOX 362 Lexington, Massachusetts 02420 DATE: October 29, 2025 Revised November 21 , 2025 Revised December 19, 2025 PATRIOT PO BOX 362 Lexington, MA 02420 VIA: Hand Delivery October 29,2025 Revised November 21, 2025 Ms.Jean Enright Director of Planning-North Andover 120 Main Street North Andover,01845 Re: 243 Great Pond Road North Andover, Massachusetts Dear Members of the Planning Board: Patriot Engineering LLC (Patriot) is pleased to submit this letter with accompanying documentation in support of the Watershed Special Permit application for the project located at 243 Great Pond Road.The proposed site improvements will involve the removal of an existing sports court area and gravel edge support of a proposed greenhouse structure.This project will not be any significant degradation of the quality or quantity of water in or entering Lake Cochichewick. The proposed greenhouse project will not result in any overcrowding or increase in traffic, is an appropriate use of the existing property and does not cause any hazards from fire or other dangers. This project does not increase the leviable area of the structure therefore overcrowding is not an issue. The existing topography for the subject parcel results in water runoff toward the west portion of the site (toward the delineated wetland); this location has been chosen as the design point for the stormwater analysis.The proposed site improvements will mimic existing drainage patterns.To mitigate any increase in stormwater runoff, the entire roof area of the proposed greenhouse will be captured and directed to proposed stone trench drip edge. The stormwater runoff from the remainder of the disturbed areas will mimic existing conditions. The proposed stone trench drip edge has been sized to capture the stormwater runoff for the 1-year, 2-year, and 10-year design storms and have a small overflow discharge in the 100-yeaar storm. The HydroCAD analysis results summarized below show that with proposed mitigation, the site improvements will not result in an increase in peak rate of stormwater surface runoff for the 1, 2, 10 and 100-year design storm. DP-1/100 Existing (Pre) Proposed (Post) Storm Event Rate(cfs) Volume(cf) Rate(cfs) Volume(cf) 1-Year(2.64 in./hr.) 0.22 935 0.16 767 2-Year(3.2 in./hr.) 0.42 1,521 0.33 1,287 10-Year(4.8 in./hr.) 1.12 3,609 0.98 3,188 100-Year(8.8 in./hr.) 3.28 10,203 3.01 9,426 Accompanying this letter is: • A"Greenhouse Site Plan" dated October 29, 2025, Revised November 21,2025 • "Stormwater Analysis and Calculations for dated October 29, 2025, Revised November 21,2025 • An"Operation & Maintenance Program" dated October 29, 2025, Revised November 21, 2025 PATRIOT PO BOX 362 Lexington, MA 02420 We anticipate this information meets the requirements of the Town of North Andover. Should you have anything further detail, please feel welcome to request via email at mnovak@patriot-eng.com PATRIOT Engineering LLC, PATRIOT E n gil�n e e r in g PO BOX 362 Lexington, MA 02420 Michael J Novak, P.E. SC- 1 EX STING DP- 1 WETLAND Subcat Reach on Link Routing Diagram for 243 GREAT POND ROAD Prepared by Patriot Engineering, Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC 243 GREAT POND ROAD Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 2 Rainfall Events Listing Event# Event Storm Type Curve Mode Duration B/B Depth AMC Name (hours) (inches) 1 1-Yr 24 Hr Type III 24-hr Default 24.00 1 2.64 2 2 2-Yr 24 Hr Type III 24-hr Default 24.00 1 3.20 2 3 10-Yr 24 Hr Type III 24-hr Default 24.00 1 4.80 2 4 100-Yr 24 Hr Type III 24-hr Default 24.00 1 8.80 2 243 GREAT POND ROAD Type///24-hr 1-Yr 24 Hr Rainfall=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment SC-1: EXISTING Runoff = 0.22 cfs @ 12.11 hrs, Volume= 935 cf, Depth= 0.45" Routed to Reach DP-1 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 1-Yr 24 Hr Rainfall=2.64" Area (sf) CN Description * 4,340 98 Court, Roof,and Patio 229 96 Gravel surface, HSG B 20,339 61 >75%Grass cover,Good, HSG B 24,908 68 Weighted Average 20,568 82.58%Pervious Area 4,340 17.42%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-1: EXISTING Hydrograph 0.24 Runoff 0.23 0.2z�r5 Type III 24-h r 0.21 018 1-Yr 24 Hr Rainfall=2.64" 0.16 Runoff Area=24,908 sf 0.14 Runoff Volume=935 cf 0.13 i 3 0.12 Runoff Depth=0.45" E: 0.11 Tc=6.0 min 0.09 0.0$ CN=68 0.06 0.05 t 0.04 ji 0.03 0.02 0.01 00,100 0 ,r,i4,.''i /,�i �e�i�e sir', ,r'i' r/i'";r;,>' 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 1-Yr 24 Hr Rainfal1=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 4 Summary for Reach DP-1: WETLAND Inflow Area = 24,908 sf, 17.42% Impervious, Inflow Depth= 0.45" for 1-Yr 24 Hr event Inflow = 0.22 cfs @ 12.11 hrs, Volume= 935 cf Outflow = 0.22 cfs @ 12.11 hrs, Volume= 935 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-1: WETLAND Hydrograph Inflow 0.24 0.22 ors D Outflow 0.22 022ors Inflow Area=24,908 sf 0.21 0. 0.2 0.19 0.17 0.16 0.15 0.14 0.13 0 0.12 a 0.1 0.08 % 0.07 0.06 0.05 rr , 0.03 0.02 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 2-Yr 24 Hr Rainfall=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment SC-1: EXISTING Runoff = 0.42 cfs @ 12.10 hrs, Volume= 1,521 cf, Depth= 0.73" Routed to Reach DP-1 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 2-Yr 24 Hr Rainfall=3.20" Area (sf) CN Description * 4,340 98 Court, Roof,and Patio 229 96 Gravel surface, HSG B 20,339 61 >75%Grass cover,Good, HSG B 24,908 68 Weighted Average 20,568 82.58%Pervious Area 4,340 17.42%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-1: EXISTING Hydrograph 0.46 Runoff 0.44. 0.4z cfs 0044 % Type III 24-hr 0.38% % 2-Yr 24 Hr Rainfall=3.20" 0.36 0.34 0.32 Runoff Area=24,908 sf 0.3 0.28 Runoff Volume=1,521 cf 0.26 0.24 0.22 j Runoff Depth=0.73" - " 08 Tc=6.0 min 0.14::::: CN=68 0.12 - 0.1 a' 0.08 0.06 0.04 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 2-Yr 24 Hr Rainfal1=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 6 Summary for Reach DP-1: WETLAND Inflow Area = 24,908 sf, 17.42% Impervious, Inflow Depth= 0.73" for 2-Yr 24 Hr event Inflow = 0.42 cfs @ 12.10 hrs, Volume= 1,521 cf Outflow = 0.42 cfs @ 12.10 hrs, Volume= 1,521 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-1: WETLAND Hydrograph Inflow 0.46M 0.42 ors 0 Outflow 0.44 0.42°rs 0.42::::: Inflow Area=24 908 sf 0.4 0.38 0.36 0.34 033 0 0.28 0.26 0.24 0 0.22 9 LL 0.2 i 0.16 0.14 00 1 0.08 - // 0.06 0.0451- /' 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 10-Vr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment SC-1: EXISTING Runoff = 1.12 cfs @ 12.10 hrs, Volume= 3,609 cf, Depth= 1.74" Routed to Reach DP-1 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 10-Yr 24 Hr Rainfall=4.80" Area (sf) CN Description * 4,340 98 Court, Roof,and Patio 229 96 Gravel surface, HSG B 20,339 61 >75%Grass cover,Good, HSG B 24,908 68 Weighted Average 20,568 82.58%Pervious Area 4,340 17.42%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-1: EXISTING Hydrograph Runoff 1.12 cfs j Type III 24-hr 1 0-Yr 24 Hr Rainfall=4.80" Runoff Area=24,908 sf j Runoff Volume=3,609 cf 3 j Runoff Depth=1.74" j LL / Tc=6.0 min CN=68 i,r,r�s.rr rrri/ Or ee /ve,0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 10-Yr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 8 Summary for Reach DP-1: WETLAND Inflow Area = 24,908 sf, 17.42% Impervious, Inflow Depth= 1.74" for 10-Yr 24 Hr event Inflow = 1.12 cfs @ 12.10 hrs, Volume= 3,609 cf Outflow = 1.12 cfs @ 12.10 hrs, Volume= 3,609 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-1: WETLAND Hydrograph Inflow 1.12 cfs p Outflow 1.12 cfs Inflow Area=24.,908 sf LL i j �i i I I r, 0,,, ,�/�/.r�//ir i�;�/ir r, i1 rl ,i,,7�r!,i 11 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment SC-1: EXISTING Runoff = 3.28 cfs @ 12.09 hrs, Volume= 10,203 cf, Depth= 4.92" Routed to Reach DP-1 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 100-Yr 24 Hr Rainfall=8.80" Area (sf) CN Description * 4,340 98 Court, Roof,and Patio 229 96 Gravel surface, HSG B 20,339 61 >75%Grass cover,Good, HSG B 24,908 68 Weighted Average 20,568 82.58%Pervious Area 4,340 17.42%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-1: EXISTING Hydrograph Runoff 3.28 cfs Type III 24-hr_ 3. 100-Yr 24 Hr Rainfall=8.80" Runoff Area=24,908 sf jRunoff Volume=10,203 cf 4 2 Runoff Depth=4.92" LL Tc=6.0 min CN=68 1. r 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 10 Summary for Reach DP-1: WETLAND Inflow Area = 24,908 sf, 17.42% Impervious, Inflow Depth= 4.92" for 100-Yr 24 Hr event Inflow = 3.28 cfs @ 12.09 hrs, Volume= 10,203 cf Outflow = 3.28 cfs @ 12.09 hrs, Volume= 10,203 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-1: WETLAND Hydrograph Inflow 3.28 cfs p Outflow 3.28 cfs _ Inflow Area=24908 sf-- u 2 /r o LL / . 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 3S BARN *-100 PROPOSE k STONE TRENCH DP-100 WETLAND Subcat Reach on Link Routing Diagram for 243 GREAT POND ROAD_POST Prepared by Patriot Engineering, Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC 243 GREAT POND ROAD—POST Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 2 Rainfall Events Listing Event# Event Storm Type Curve Mode Duration B/B Depth AMC Name (hours) (inches) 1 1-Yr 24 Hr Type III 24-hr Default 24.00 1 2.64 2 2 2-Yr 24 Hr Type III 24-hr Default 24.00 1 3.20 2 3 10-Yr 24 Hr Type III 24-hr Default 24.00 1 4.80 2 4 100-Yr 24 Hr Type III 24-hr Default 24.00 1 8.80 2 243 GREAT POND ROAD—POST Type///24-hr 1-Yr 24 Hr Rainfall=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 3S: BARN Runoff = 0.05 cfs @ 12.08 hrs, Volume= 179 cf, Depth= 2.41" Routed to Pond PT:STONE TRENCH Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 1-Yr 24 Hr Rainfall=2.64" Area (sf) CN Description * 890 98 DRIVE 890 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 3S: BARN Hydrograph 0.055 0 Runoff 0.05 cfs 0.05 Type III 24-h r 0.045 j 1 -Yr 24 Hr Rainfall=2.64" 0.04 % Runoff Area=890 sf_ Runoff Volume=179 d 0.035 0.03 Runoff Depth=2.41 - a 0.025 Tc=6.0 min 0.02 - i CN=98- 0.015 � 0.01 / - 0.005 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 1-Yr 24 Hr Rainfall=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment SC-100: PROPOSED Runoff = 0.16 cfs @ 12.12 hrs, Volume= 767 cf, Depth= 0.38" Routed to Reach DP-100 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 1-Yr 24 Hr Rainfall=2.64" Area (sf) CN Description * 3,050 98 Ex. Roof, Ex. Patio, Prop Wall and Landings 156 85 Gravel roads, HSG B 20,812 61 >75%Grass cover,Good, HSG B 24,018 66 Weighted Average 20,968 87.30%Pervious Area 3,050 12.70%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-100: PROPOSED Hydrograph 0.18 0.17 � Runoff 0.16 - Type III 24-hr 0.15 0.14 1-Yr 24 Hr Rainfall=2.-64" 0.13 0.12 Runoff Area=24,018 sf 0.11 Runoff Volume=767 cf 4 0.1 3 0.09 Runoff Depth=0.38" M 0.08 0.07 Tc=6.0 m i n 0.06 0.05 0.04 'i 0.03 / 0.02 0.01 /r/ z//r% ir/ ° ,r,r�,i!% /,� riri.. ... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 1-Yr 24 Hr Rainfal1=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 5 Summary for Reach DP-100: WETLAND Inflow Area = 24,908 sf, 15.82% Impervious, Inflow Depth= 0.37" for 1-Yr 24 Hr event Inflow = 0.16 cfs @ 12.12 hrs, Volume= 767 cf Outflow = 0.16 cfs @ 12.12 hrs, Volume= 767 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-100: WETLAND Hydrograph 0.18 IM Inflow 0.16 cfs - - _ _ 0 Outflow 0.1' 0.16 cfs 0.16 Inflow Area=24,908 sf 0.15 0.14 ME 0.13 0.12 0.11 a 3 0.09 i—°° 0.08 0.06 0.05 0.03 0.02 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD-POST Type///24-hr 1-Yr 24 Hr Rainfall=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 6 Summary for Pond PT: STONE TRENCH Inflow Area = 890 sf,100.00% Impervious, Inflow Depth= 2.41" for 1-Yr 24 Hr event Inflow = 0.05 cfs @ 12.08 hrs, Volume= 179 cf Outflow = 0.01 cfs @ 11.70 hrs, Volume= 179 cf, Atten=85%, Lag=0.0 min Discarded = 0.01 cfs @ 11.70 hrs, Volume= 179 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routed to Reach DP-100 :WETLAND Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Peak Elev=152.91' @ 12.57 hrs Surf.Area=140 sf Storage=51 cf Plug-Flow detention time= 39.8 min calculated for 179 cf(100%of inflow) Center-of-Mass det.time= 39.7 min (800.4-760.6) Volume Invert Avail.Storage Storage Description #1 152.00' 224 cf Custom Stage Data(Prismatic) Listed below(Recalc) 560 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.00 140 0 0 156.00 140 560 560 Device Routing Invert Outlet Devices #1 Discarded 152.00' 2.410 in/hr Exfiltration over Surface area #2 Primary 155.95' 10.0'long x 1.0'breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 11.70 hrs HW=152.04' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.00' (Free Discharge) t2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) 243 GREAT POND ROAD—POST Type///24-hr 1-Yr 24 Hr Rainfall=2.64" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 7 Pond PT: STONE TRENCH Hydrograph Inflow o.os ifs ..l Outflow Inflow Area-890 sf Discarded p Primary 0.055 0.05 Peak Elev=152.91 '- 0.045. Storage=51 cf 0.04... 0.035 a 0.03 3 a 0.025 0.02 0.015 0.01 cfs . 0.01 cfs 0.01 0.005 0.00 cfs i, 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 2-Yr 24 Hr Rainfall=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 3S: BARN Runoff = 0.06 cfs @ 12.08 hrs, Volume= 220 cf, Depth= 2.97" Routed to Pond PT:STONE TRENCH Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 2-Yr 24 Hr Rainfall=3.20" Area (sf) CN Description * 890 98 DRIVE 890 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 3S: BARN Hydrograph 0.07 0 Runoff 0.065 0.0s ors 0.06 Type III 24-h r 0.055 j 2-Yr 24 Hr Rainfall=3,20 0.05 % -Runoff Area=890 sf-- Runoff 0.045 0.04 - - �Ru f�Vo lu m cf e=220 u00 -- 3 0.035 - Runoff Depth=2.97 o - 0.03 Tc=6.0 min 0.025 j 0.02 CN=98 - / - 0.015 0.01 t �r 0.005 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 2-Yr 24 Hr Rainfall=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment SC-100: PROPOSED Runoff = 0.33 cfs @ 12.11 hrs, Volume= 1,287 cf, Depth= 0.64" Routed to Reach DP-100 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 2-Yr 24 Hr Rainfall=3.20" Area (sf) CN Description * 3,050 98 Ex. Roof, Ex. Patio, Prop Wall and Landings 156 85 Gravel roads, HSG B 20,812 61 >75%Grass cover,Good, HSG B 24,018 66 Weighted Average 20,968 87.30%Pervious Area 3,050 12.70%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-100: PROPOSED Hydrograph 0.36 Runoff 0.33 cfs 0.34 0.32 Type III 24-h r 028 2-Yr 24 Hr Rainfall=3.20" 0.26 j Runoff Area=24,018 sf 0.24 ,.., 0.22 Runoff Volume=1,287 cf o 18 Runoff Depth=0,64" a 0.16 Tc=6.0 m i n 0.14 0.12 ! CN=66 0.1 0.08 0.06 0.04 �® OL11 11, 11 11 11........... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 2-Yr 24 Hr Rainfal1=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 10 Summary for Reach DP-100: WETLAND Inflow Area = 24,908 sf, 15.82% Impervious, Inflow Depth= 0.62" for 2-Yr 24 Hr event Inflow = 0.33 cfs @ 12.11 hrs, Volume= 1,287 cf Outflow = 0.33 cfs @ 12.11 hrs, Volume= 1,287 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-100: WETLAND Hydrograph Inflow 0.36 oss ors 0 Outflow 0.34 °.33 Inflow Area=24,908 sf 0.32 0.3 0.28 0.26 0.24 0.22 l w 0.2 r 3 0.18 a 0.16 0.14 0.12 0.1 0.08r ® r 0.06 0.04 0.02 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD-POST Type///24-hr 2-Yr 24 Hr Rainfall=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 11 Summary for Pond PT: STONE TRENCH Inflow Area = 890 sf,100.00% Impervious, Inflow Depth= 2.97" for 2-Yr 24 Hr event Inflow = 0.06 cfs @ 12.08 hrs, Volume= 220 cf Outflow = 0.01 cfs @ 11.64 hrs, Volume= 220 cf, Atten=88%, Lag=0.0 min Discarded = 0.01 cfs @ 11.64 hrs, Volume= 220 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routed to Reach DP-100 :WETLAND Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Peak Elev=153.22' @ 12.64 hrs Surf.Area=140 sf Storage=68 cf Plug-Flow detention time= 56.0 min calculated for 220 cf(100%of inflow) Center-of-Mass det.time= 55.9 min (812.3-756.4) Volume Invert Avail.Storage Storage Description #1 152.00' 224 cf Custom Stage Data(Prismatic) Listed below(Recalc) 560 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.00 140 0 0 156.00 140 560 560 Device Routing Invert Outlet Devices #1 Discarded 152.00' 2.410 in/hr Exfiltration over Surface area #2 Primary 155.95' 10.0'long x 1.0'breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 11.64 hrs HW=152.04' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.00' (Free Discharge) t2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) 243 GREAT POND ROAD—POST Type///24-hr 2-Yr 24 Hr Rainfall=3.20" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 12 Pond PT: STONE TRENCH Hydrograph Inflow 0.06 ofs ..III Outflow Inflow Area-890 sf Discarded 0.07 ®Primary 0.065(1 0.06 Peak Elev=153.22' 0.06 0.055 Storage=68 cf - 0.05 0.045 v 0.04 3 0.035 0 a 0.03 0.025 0.02 0.01 cfs ., .... 0.015 O.o1 cfs 0.01 0.0 .: 0.00 cfs 0,,;; 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 10-Vr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment 3S: BARN Runoff = 0.10 cfs @ 12.08 hrs, Volume= 338 cf, Depth= 4.56" Routed to Pond PT:STONE TRENCH Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 10-Yr 24 Hr Rainfall=4.80" Area (sf) CN Description * 890 98 DRIVE 890 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 3S: BARN Hydrograph 0.105 0 Runoff 0.1. 0.10 cfs 0.095 j Type III 24-hr 10-Yr 24 Hr Rainfall=4.80 0.085 0.08 0.075 Runoff Area=890 sf 0.07 0.065 Runoff Vol ume=338 cf w 0.06 05 % Runoff Depth=4.516 0 0.0.05 u-0.045 Tc=6.0 m i n 0. 0 0035 ; CN=98 0.03 0.025 0.02 0.015 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 10-Vr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment SC-100: PROPOSED Runoff = 0.98 cfs @ 12.10 hrs, Volume= 3,188 cf, Depth= 1.59" Routed to Reach DP-100 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 10-Yr 24 Hr Rainfall=4.80" Area (sf) CN Description * 3,050 98 Ex. Roof, Ex. Patio, Prop Wall and Landings 156 85 Gravel roads, HSG B 20,812 61 >75%Grass cover,Good, HSG B 24,018 66 Weighted Average 20,968 87.30%Pervious Area 3,050 12.70%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-100: PROPOSED Hydrograph Runoff 1 0.98 cfs Type III 24-hr 10-Yr 24 Hr Rainfall=4.80" Runoff Area=24,018 sf Runoff Volume=3,188 cf Runoffs Depth=1.59' Tc=6.0 m i n j CN=66 ri 0...,, ,% ;e11 �%e 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 10-Yr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 15 Summary for Reach DP-100: WETLAND Inflow Area = 24,908 sf, 15.82% Impervious, Inflow Depth= 1.54" for 10-Yr 24 Hr event Inflow = 0.98 cfs @ 12.10 hrs, Volume= 3,188 cf Outflow = 0.98 cfs @ 12.10 hrs, Volume= 3,188 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-100: WETLAND Hydrograph Inflow o.ss its ®Outflow 0.98`. Inflow Area=24,908 sf 3 0 LL 0,,, ,�/r 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD-POST Type///24-hr 10-Yr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 16 Summary for Pond PT: STONE TRENCH Inflow Area = 890 sf,100.00% Impervious, Inflow Depth= 4.56" for 10-Yr 24 Hr event Inflow = 0.10 cfs @ 12.08 hrs, Volume= 338 cf Outflow = 0.01 cfs @ 11.25 hrs, Volume= 338 cf, Atten=92%, Lag=0.0 min Discarded = 0.01 cfs @ 11.25 hrs, Volume= 338 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routed to Reach DP-100 :WETLAND Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Peak Elev=154.19' @ 13.03 hrs Surf.Area=140 sf Storage=123 cf Plug-Flow detention time= 112.6 min calculated for 338 cf(100%of inflow) Center-of-Mass det.time= 112.5 min (861.2-748.7) Volume Invert Avail.Storage Storage Description #1 152.00' 224 cf Custom Stage Data(Prismatic) Listed below(Recalc) 560 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.00 140 0 0 156.00 140 560 560 Device Routing Invert Outlet Devices #1 Discarded 152.00' 2.410 in/hr Exfiltration over Surface area #2 Primary 155.95' 10.0'long x 1.0'breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 11.25 hrs HW=152.04' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=152.00' (Free Discharge) t2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) 243 GREAT POND ROAD—POST Type///24-hr 10-Yr 24 Hr Rainfall=4.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 17 Pond PT: STONE TRENCH Hydrograph Inflow 0.10 cfs QQ ..III Outflow Inflow Area-8aJO Sf Discarded ® 0.105 Primary 0.1 0.095(1 Peak Elev=154.19' °o 08 Storage=123 cf 0.075 0.07 ^0.065 w 0.06 0.055 0 0.05 a 0.045 0.04 0.035 0.03 0.025 0.01 cfs ... 0.02 0.015 0.0�cfs 0.01 gym" 0.0 0.00 cfs °..i.. 0%2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 3S: BARN Runoff = 0.18 cfs @ 12.08 hrs, Volume= 635 cf, Depth= 8.56" Routed to Pond PT:STONE TRENCH Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 100-Yr 24 Hr Rainfall=8.80" Area (sf) CN Description * 890 98 DRIVE 890 100.00%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment 3S: BARN Hydrograph 0.19 0 Runoff 0.18 0.18 cfs 0.17 j Type III 24-hr 100-Yr 24 Hr Rainfall=8.80" 0.15 - - - 0.14 Runoff Area=890 sf 0.13 0.12 j Runoff Volume=635 cf 3 0.1 j/ Runoff Depth=88.56 LL Tc=6.0 min 0.08 0.07 % CN=98 0.06 ' 0.05 0.04 i - 0.03 - 0.02 0.01 �r�r r i r ° 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment SC-100: PROPOSED Runoff = 3.01 cfs @ 12.09 hrs, Volume= 9,351 cf, Depth= 4.67" Routed to Reach DP-100 :WETLAND Runoff by SCS TR-20 method, UH=SCS,Weighted-CN,Time Span=0.00-30.00 hrs,dt=0.03 hrs Type III 24-hr 100-Yr 24 Hr Rainfall=8.80" Area (sf) CN Description * 3,050 98 Ex. Roof, Ex. Patio, Prop Wall and Landings 156 85 Gravel roads, HSG B 20,812 61 >75%Grass cover,Good, HSG B 24,018 66 Weighted Average 20,968 87.30%Pervious Area 3,050 12.70%Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment SC-100: PROPOSED Hydrograph Runoff 3.01 cfs - - -. 3... / Type III 24-hr j100-Yr 24 Hr Rainfall=8.80" jRunoff Area=24,018 sf Runoff Volume=9,351 cf w Runoff Deg th=4.67' j p %% Tc=6.0 min LL CN=66 0,.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD—POST Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD®10.20-5c s/n 11576 @ 2023 HydroCAD Software Solutions LLC Page 20 Summary for Reach DP-100: WETLAND Inflow Area = 24,908 sf, 15.82% Impervious, Inflow Depth= 4.54" for 100-Yr 24 Hr event Inflow = 3.01 cfs @ 12.09 hrs, Volume= 9,426 cf Outflow = 3.01 cfs @ 12.09 hrs, Volume= 9,426 cf, Atten=0%, Lag=0.0 min Routing by Stor-Ind+Trans method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Reach DP-100: WETLAND Hydrograph Inflow 3.01 cfs _ ®Outflow 3.01 cfs Inflow Area=24,908 sf 3 LL i 0,.. �/�� 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 243 GREAT POND ROAD-POST Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 21 Summary for Pond PT: STONE TRENCH Inflow Area = 890 sf,100.00% Impervious, Inflow Depth= 8.56" for 100-Yr 24 Hr event Inflow = 0.18 cfs @ 12.08 hrs, Volume= 635 cf Outflow = 0.09 cfs @ 12.31 hrs, Volume= 635 cf, Atten=49%, Lag= 13.3 min Discarded = 0.01 cfs @ 9.72 hrs, Volume= 560 cf Primary = 0.08 cfs @ 12.31 hrs, Volume= 75 cf Routed to Reach DP-100 :WETLAND Routing by Stor-Ind method,Time Span=0.00-30.00 hrs,dt=0.03 hrs Peak Elev=155.97' @ 12.30 hrs Surf.Area=140 sf Storage=222 cf Plug-Flow detention time= 204.1 min calculated for 634 cf(100%of inflow) Center-of-Mass det.time= 204.1 min (944.1-740.1) Volume Invert Avail.Storage Storage Description #1 152.00' 224 cf Custom Stage Data(Prismatic) Listed below(Recalc) 560 cf Overall x 40.0%Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 152.00 140 0 0 156.00 140 560 560 Device Routing Invert Outlet Devices #1 Discarded 152.00' 2.410 in/hr Exfiltration over Surface area #2 Primary 155.95' 10.0'long x 1.0'breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 9.72 hrs HW=152.04' (Free Discharge) t1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.06 cfs @ 12.31 hrs HW=155.97' (Free Discharge) t2=Broad-Crested Rectangular Weir (Weir Controls 0.06 cfs @ 0.35 fps) 243 GREAT POND ROAD—POST Type///24-hr 100-Yr 24 Hr Rainfall=8.80" Prepared by Patriot Engineering Printed 11/21/2025 HydroCAD°10.20-5c s/n 11576 ©2023 HydroCAD Software Solutions LLC Page 22 Pond PT: STONE TRENCH Hydrograph Inflow 0.1a cfs ..III Outflow Inflow Area=890 sf Discarded 0.19 0 Primary 8fl 0.17 Peak Elev=155.97' 0.16 0.14 Storage=222 cf 0.13 0.12 0.09 cfs 0.11 0.1 _2 0.09 o.oa cfs 1 0.08 - -. 0.07 0.06 0.05 0.04 0.03 m 0.01 cfsIN 0.02 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) Project Name: 243 Great Pond Road North Andover, MA Applicants: Stephen and Judi Boyko 243 Great Pond Road North Andover, MA Party Responsible for Maintenance During Construction: Contractor Party Responsible for Maintenance After Construction: Property Owner Erosion and Sedimentation Control Measures during Construction Activities Filtermitt Filtermitt will be installed along the down gradient limit of work as depicted on the Site Construction Plan. The Filtermitt will be installed prior to the commencement of any work on- site. An additional supply of Filtermitt shall be on-site to replace and/or repair Filtermitt that is disturbed. The lines of Filtermitt shall be inspected and maintained on a weekly basis during construction. No construction activities are to occur beyond the Filtermitt at any time. Sediment shall be removed once the volume reaches '/4 to %2 the height of the Filtermitt. Surface Stabilization The surface of all disturbed areas shall be stabilized during and after construction. Disturbed areas remaining idle for more than 14 days shall be stabilized. Temporary measures shall be taken during construction to prevent erosion and siltation. No construction sediment shall be allowed to enter any infiltration system or formal drainage system. All disturbed slopes will be stabilized with a permanent vegetative cover. Some or all of the following measures will be utilized on this project as conditions may warrant. a. Temporary Seeding b. Temporary Mulching C. Permanent Seeding d. Placement of Sod e. Hydroseeding f. Placement of Hay g. Placement of Jute Netting Dust shall be controlled at the site. Tree Protection Existing trees to be saved shall be protected with orange construction fence (offset from the tree trunk by professional standard based on canopy). Stone Edge Construction activity above and around the proposed location of the stone edge facility shall be limited to prevent compaction of the existing soil. Installation of this system shall occur under dry weather conditions and full stone depth shall be installed immediately to prohibit the introduction of fines or other material that would compromise the functionality of this system. Removal of Sediment and Erosion Controls At the completion of construction activities and after receiving approval from the Town of North Andover, all physical sediment and erosion controls shall be removed from the site. Long-Term Inspection and Maintenance Measures after Construction Erosion Control Eroded sediments can adversely affect the performance of the stormwater management system. Eroding or barren areas should be immediately re-vegetated. Debris and Litter Removal Trash may collect in the BMP's, potentially causing clogging of the facilities. All debris and litter shall be removed when necessary, and after each storm event. Sediment and debris collected from vacuuming and/or sweeping should be disposed of at a permitted waste disposal facility. Avoid disposing of this material on site Stone Drip Edge The drip edge shall be inspected after all major storms and on regular bi-annual scheduled dates. The drip edge shall be cleared of any debris on a biannual basis. The first 1/2 inch of stone can be removed and replaced if the edge becomes clogged Debris and Litter Removal Trash may collect in the BMP's, potentially causing clogging of the facilities. All debris and litter shall be removed when necessary, and after each storm event. Sediment and debris collected from vacuuming and/or sweeping should be disposed of at a permitted waste disposal facility. Avoid disposing of this material on site STORMWATER MANAGEMENT CONSTRUCTION PHASE INSPECTION SCHEDULE AND EVALUATION CHECKLIST PROJECT LOCATION: 243 Great Pond Road WEATHER: Inspecti Required Follow-up Inspect Area Comments Recommendat Inspection on Inspection Required Date or Inspected Frequency if ion (yes/no) BMP Filtermitt Weekly and After Major Storm Events (1) Refer to the Massachusetts Stormwater Handbook, Volume Two: Stormwater Technical Handbook (February 2008) for recommendations regarding frequency for inspection and maintenance of specific BMP's. (2) Inspections to be conducted by a qualified professional such as an environmental scientist or civil engineer. Limited or no use of sodium chloride salts, fertilizers or pesticides recommended. Other notes: (Include deviations from: Con. Comm. Order of Conditions, PB Approval, Construction Sequence and Approved Plan) Stormwater Control Manager: STORMWATER MANAGEMENT AFTER CONSTRUCTION INSPECTION SCHEDULE AND EVALUATION CHECKLIST PROJECT LOCATION: 243 Great Pond Road WEATHER: Inspecti Required Follow-up Inspect Area Inspected Ins ection Comments Recommenda Inspection on or p ion Required Date Frequency if (yes/no) BMP Drip Edge Bi-annually and After Major Storm Events (3) Refer to the Massachusetts Stormwater Handbook, Volume Two: Stormwater Technical Handbook (February 2008) for recommendations regarding frequency for inspection and maintenance of specific BMP's. (4) Inspections to be conducted by a qualified professional such as an environmental scientist or civil engineer. Limited or no use of sodium chloride salts, fertilizers or pesticides recommended. Other notes: (Include deviations from: Con. Comm. Order of Conditions, PB Approval, Construction Sequence and Approved Plan) Stormwater Control Manager: